Houston, TX 77005
12:00 p.m. Monday, Feb. 18, 2013
On Campus | Alumni
DMSP satellites have proven to be quite useful for dayside and nightside investigations of the magnetosphere. DMSP observations on the nightside infer that during northward interplanetary magnetic field (IMF) conditions, there is massive entry of magnetosheath particles leading to the formation of a cold, dense plasma sheet. The plasma sheet ion cold component, which is similar to the magnetosheath ion population, is heated on the dawnside but not on the duskside, which suggests different solar wind entry processes operating at the dawn and dusk flanks. On the other hand, the magnetoshperic ion hot component is hotter on the duskside than the dawnside, which can be attributed to the transport processes internal to the magnetosphere such as curvature and gradient drifts. The dawn-dusk assymmetries give rise to the single Maxwellian, double Maxwellian, and Kappa distributions of ions observed in the plasma sheet. The total entropy of a flux tube is reduced by an order of magnitude after reconnection, but the specific entropy (p/??) remains more or less the same. The cold population specific entropy increases by a factor of 5 from the flanks to the midnight meridian, which provides a constraint for transport mechanism(s) within the plasma sheet. Nonconservation of specific entropy is expected to occur when nonadiabatic processes such as wave-particle interactions, heat flux, and dissipation are operating and when the fluid element loses its integrity as occurs when hot particles and cold particles move differently. DMSP observations on the dayside show that Region-1 (R1) J// responses to variations in Vsw and nsw at 08 – 16 MLT suggest that R1 at these local times are frequently open while R1 at 06 – 08 and 17 – 18 MLTs are frequently closed. R2 is located mostly on closed field lines. In the afternoon open R1 at 12 – 16 MLTs, an increase in nsw increases J//, decreases maximum peak Ee (proxy for ??//), but has little effect on maximum ?. In the same R1 region, an increase in Vsw increases J//, maximum peak Ee, and maximum ?. The dependencies of J//, maximum peak Ee, and maximum ? are consistent with the Knight relation and the voltage generator at the magnetopause boundary in the afternoon open R1. Finally, the observations are compared with quasi-stationary low latitude boundary layer (LLBL) – FAC coupling model calculations.